## **Core Concept**
Wolff-Parkinson-White (WPW) syndrome is a condition characterized by the presence of an accessory electrical pathway between the atria and ventricles, known as the **Bundle of Kent**. This pathway can cause the heart to beat too quickly, leading to tachycardia. Reentrant tachycardias occur when there is a circuit of electrical activity that re-enters and continues to stimulate the heart.

## **Why the Correct Answer is Right**
The most common reentrant tachycardia associated with WPW syndrome is **Orthodromic Atrioventricular Reentrant Tachycardia (AVRT)**. In orthodromic AVRT, the electrical impulse travels down the **AV node** and then back up the **accessory pathway** (antegrade conduction down the AV node and retrograde conduction up the accessory pathway). This is the most common type of tachycardia in WPW syndrome because the circuit involves the AV node and the accessory pathway, leading to a rapid heart rate.

## **Why Each Wrong Option is Incorrect**
* **Option A:** Antidromic AVRT involves conduction down the accessory pathway and up the AV node, which is less common than orthodromic AVRT.
* **Option B:** Atrial fibrillation with rapid ventricular response can occur in WPW syndrome but is not a reentrant tachycardia in the same sense as AVRT.
* **Option D:** AV nodal reentrant tachycardia (AVNRT) does not involve an accessory pathway and is a different mechanism of tachycardia.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that patients with WPW syndrome are at risk for developing **atrial fibrillation**, which can lead to a rapid ventricular response and potentially degenerate into **ventricular fibrillation**. The presence of a **delta wave** on an electrocardiogram (ECG) is a hallmark of WPW syndrome.

## **Correct Answer:** . Orthodromic Atrioventricular Reentrant Tachycardia (AVRT)